engine reving on it's own.

[jasonmolinar]

So my engine light came on like a week ago and I haven't had time to take it in yet. But today it started reving on it's own. Like when it's out of gear it will just stay reved up to 2000 rpm non stop, but when I'm in gear it only revs when I'm stopped, but not as strong or as long, just little spurts. Any ideas what's wrong?

 

[Ggg]

I think we need to know what vehicle this is. Or just list your vehicle and location in your info and it will always be there like in my post here.

 

[jfrabat]

First guess would be vacuum leak...

 

[sweetpeet]

What jeep are you talking about???? But Yah I'd go with vacume leak or maybe injector issue just a guess. Need to know what jeep. But this the first I've heard of this issue. Let us know what's wrong when it's all over.

 

[jasonmolinar]

Sorry haha. It's a 2002 tj. I only have the iPhone app so it won't let me load any of the stats stuff

 

[JPNinPA]

Take anything apart lately? Leak at the intake. Could be anywhere from the TB to intake or any of the cylinders. Though I would expect one cylinder misfiring or the intake isn't seated properly. Also be sure all vacuum lines to the intake are attached and nor cracked or missing.

 

[jasonmolinar]

Well I took the ignition coil out to put a new one in but then realized I didn't have a clamp for the new one so I put the old one back on, and everything seemed to go back in fine. But I'll check out all that other stuff tomorrow when the sun is out

 

[Ggg]

On ECM equipped Jeeps I have seen this happen only twice. Your TJ has the alternator output controlled by the ECM. If it senses low battery voltage it will increase idle to allow the alternator to compensate. Check your alternator output and battery condition. Both times I saw this it was an alternator going bad.
Vacuum leaks will not cause a engine light to come on, a bad alternator will.

 

[Gr8tdragon]

Like the other guys said...look for leaks on the intake manifold. If there is no leaks then I would look for codes in the computer as the next item that could cause this is the idle air adjuster that is controlled by the computer. If the adjuster is failed in the open position it would cause your vehicle to rev.

 

[redwrangler02]

Not that this is the issue, but I had that same thing happening to my 02 Wrangler Sport, and it turned out to be the TPS. Once I replaced that, it was fine.